4-(thiazolyl) pyridinium salts and 4-(oxazolyl) pyridinium salts for lowering blood glucose levels

ABSTRACT

COMPOSITIONS CONTAINING THIAZOLYLPYRIDINIUM SALTS AND OXAZOLYLPYRIDINIUM SALTS ARE DESCRIBED. THE USE OF THESE COMPOSITIONS AS A MEANS FOR THE LOWERING OF BLOOD GLUCOSE LEVELS IN WARM-BLOODED ANIMALS IS DESCRIBED.

United States Patent O Int. Cl. A61k 27/00 US. Cl. 424263 ClaimsABSTRACT on THE DISCLOSURE Compositions containing thiazolylpyridiniumsalts and oxazolylpyridinium salts are described. The use of thesecompositions as a means for the lowering of blood glucose levels inwarm-blooded animals is described.

This application is a continuation-in-part of our application Ser. No.690,382, filed Dec. 14, 1967 now abandoned which is acontinuation-in-part of application Ser. No. 669,705, filed Sept. 22,1967, now abandoned.

The new compositions of the present invention contain as the activecomponent compounds of the following formula:

R is selected from the group consisting of hydrogen, methyl andcyclopropyl; R is selected from the group consisting of alkenyl (C -Calkyl (C -C and ethoxyethyl; X is a sulfur or an oxygen atom, and Y is apharmaceutically acceptable anion such as, for example, chloride,bromide, iodide, and the like.

In general, the active components are crystalline solids, soluble inwater.

The active components of the present invention may be prepared byreaction of a thiazolylpyridine or an oxazolylpyridine with an alkenyl(C -C alkyl (C -C or ethoxyethyl halide at a temperature of 0 to C. withor without a solvent, such as an alcohol, for a period of time ofseveral minutes to twenty-four hours in an open vessel or a sealed bomb.The time necessary to complete the reaction is dependent upon thetemperature and other conditions of the reaction. This reaction can beillustrated schematically by the following equation:

wherein R, R X and Y are as described hereinbefore. Among the compoundsof the present invention are,

for example:

1-rnethyl-(4anethyI-Z-thiazolyhpyridinium iodide;

l-allyl-4-(4-methyl-2-thiazolyl)pyridinium chloride;

1-methylallyl-4- 4-cyclopropyl-Z-thiazolyl) pyridinium bromide;

ice

1-ethyl-4- 2-methyl-4-thiazolyl pyridinium iodide;

1-methyl-4- Z-oxazolyl pyridinium iodide;

1- (Z-ethoxyethyl) -4- (4-methyl-2-oxazolyl pyridinium bromide;

1-(2-butene-1-yl)-4-(5-4oxaz1olyl)pyridinium chloride.

The compositions of the present invention show the ability to lowerblood glucose in Warm-blooded animals. When the compositions areadmiistered orally to normal mice or alloxanized mice, a reduction ofblood sugar levels is observed. The active components of this inventionare administered by gavage as saline solutions or aqueouscarboxymethyl-cellulose suspensions to CF-l mice (Carworth Farms, 18-25grams, 4-6 animals). Control animals receive an equivalent volume ofvehicle. Food is withheld from animals after dosing. Blood glucose isdetermined in 0.05 milliliter samples of blood by the method of Hoifman[1. Biol. Chem., 120, 51 (1937)] as adapted to the TechniconAutoAnalyzer and is expressed as percent change from predose values. Thedata are shown in the table hereinafter.

TABLE I.-DECREASE IN BLOOD GLUCOSE IN NORMAL MICE AFTER ORALADMINISTRATION OF THIAZOLYL- PYRIDINIUM SALTS AND OXAZOLYLPYRIDINIUMSALTS Percent Dose, Hours decrease mmoles/ after in blood Compound kg.dosing glucose 1-methyl-4-(4-methyl-2-thiazolyl) pyridinlum chloride 0.8 4 90: 2 l-methyli-(4-methyl-2-thiazolyl) pyridinlum iodide 0. 8 6 6816 1-ethyl-4-(4-methyl-2-thiazolyl) pyridinium bromide 1. 5 3 $4: 21-'n-propyl-4-(4-ruethyl-2-thiaZolyl) pyridinium bromide 1. 5 5 71a: 71-allyl-4-(4-methyl-2-thiazolyl) pyridiuiuln chloride 1. 5 3 :181-(2-eth0xyethyl)4-(4-methyl-2- thiazolyDpyridinium chloride 1. 5 3 84=5 1-methyl-4-(5-methyl-2-thiazoly1) pyridinium iodide 0. 5 5 (59: 4l-methyl-i-(2methyl-4'thiazolyl) pyridinium chloride 1. 6 4 64* 121-ethyl-4-(2-methyl4-thiazolyl) pyridinium bromide 1. 5 3 37=i= 8l-n-propyl-4-(2methyl-4-thiazolyl) pyridinium bromide 1.0 3 49s: 91-allyl-4-(2-methyl-4-thiazolyl) pyridinium chloride 1.0 5 37 31-(2-methylallyl)-4-(2-methyl4- thiazolybpyridinium chloride 1. 5 3 31:5 1-(2-ethoxyethyl) ta-methyl tthiazolyl) pyridinium chloride 1. 5 3 53*11 1-methyl-4-(2-cyclopropyl-4-thiazolyl)- pyridinium iodide 1.0 3 64:18l-methyll-(Z-methyl-dthiazolyl) pyridinium iodide 1. 0 5 33* 51-methy1-4-(2-oxazolyl) -pynd1n1um chloride 3. 0 3 651131-methyl-4-(5-methyl-2-oxazolyl) pyridinium iodide 3.0 3 83 41-methyl-4-(2-methyl-5-oxazolyl) pyridinium iodide 3. 0 5 47: 71-ethy1-4-(2-oxazolyi)-pyridinium bromide 3.0 5 61: 71-allyl-4-(2-oxazolyl) -pyridin1um chloride 3.0 5 4 7 The above resultsshow that the active components of the present invention are useful inlowering the blood glucose concentration in normal warm-blooded animals.

The ability of the present compounds to lower blood glucose in diabeticmice is measured as follows: The animals used are male CF 1S mice whichhave been previously injected intravenously with alloxan monohydratemg./kg.) and blood glucose determined 7 days later. Only those animalswith blood glucose levels 2250 mg./ ml. are used. The present compoundsare administered by gavage at the indicated levels as saline solutions.Control animals receive an equivalent volume of vehicle. Food iswithheld from the animals after dosing. Blood glucose is determined on0.02 ml. samples of blood by the method of Hoifman [J. Biol. Chem., 120,51 (1937)] as adapted to the Teehnicon AutoAnalyzer and expressed 3 asmg./100 ml. The results are summarized in Table II as follows:

concentrated to an oily residue, which on distillation at l20-l25 C./2.5mm. gives an oil. The oil solidifies on TABLE II.EFFECT OF PYRIDINIUMSALTS N BLOOD GLUCOSE OF ALLOXAN-TREATED MICE Blood glucose, mg./l00ml.,

The compositions of the present invention may be used to lower bloodsugar levels in warm-blooded animals at a dose of from 0.1 milligram to100 milligrams per kilogram of body weight per day. They may beadministered in dosage units of from 5 mg. to 500 mg. per dose.Obviously, the unit may be taken in multiples or divided into a smallerdose.

The active components of this invention can be used withpharmaceutically acceptable carriers in compositions such as tablets,wherein the principal active ingredient is mixed with conventionaltableting ingredients such as corn starch, lactose, sucrose, sorbitol,talc, stearic acid, magnesium stearate, dicalcium phosphate, gums, andfractionally similar materials as pharmaceutical diluents or carriers.The tablets or pills of the novel compositions can be laminated orotherwise compounded to provide a dosage form affording the advantage ofprolonged or delayed action or predetermined successive action of theenclosed medication. For example, the tablet or pill can comprise aninner dosage and an outer dosage component, the latter being in the formof an envelope over the former. The two components can be separated byan enteric layer which serves to resist disintegration in the stomachand permits the inner component to pass intact into the duodenum or tobe delayed in release. A variety of material can be used for suchenteric layers or coatings, such materials including a number ofpolymeric acids or mixtures of polymeric acids with such materials asshellac, shellac and cety] alcohol, cellulose acetate and the like. Aparticularly advantageous enteric coating comprises a styrene maleicacid copolymer together with known materials contributing to the entericproperties of the coating. The term dosage form as described hereinrefers to physically discrete units suitable as unitary dosage forWarm-blooded animal subjects, each unit containing a predeterminedquantity of active material calculated to produce the desiredtherapeutic effect in association with the required pharmaceuticaldiluent, carrier or vehicle. Examples of suitable oral dosage forms inaccord with this invention are tablets, capsules, pills, powder packets,granules, wafers, cachets, teaspoonfuls, dropperfuls, ampules, vials,segregated multiples of any of the foregoing and other forms as hereindescribed.

DETAILED DESCRIPTION The preparation of the active components of thecompositions of this invention will be described in greater detail inconjunction with the following examples.

Example 1.Preparation of 4-(4-methyl-2-thiazolyl) pyridine A mixture ofg. of thioisonicotinamide and 10.8 g. of chloroacetone in 50 ml. ofethanol is refluxed for 6 hours. The reaction mixture is concentratedunder reduced pressure and the residue is dissolved in water. Theaqueous solution is made alkaline with sodium hydroxide solution andextracted with ether. The ether extracts are dried and standing and isrecrystallized from hexane to give colorless crystals, melting point72-73 C.

Example 2.Preparation of 4-(5-methyl-2-thiazolyl)pyridine A mixture of 2g. of a-isonicotinamidoacetone and 3 g. of phosphorus pentasulfide isheated in an oil bath at C. until gas evolution ceases. The solid massis heated with excess 1 N potassium hydroxide solution and the resultingmixture is extracted with chloroform. The chloroform solution is driedand concentrated to give a tan solid. Sublimation at 65 C./0.05 mm.provides yellow crystals, melting point 88 C.

Example 3.Preparation of 4-(2-methyl-4-thiazolyl) pyridine A mixture of2.3 g. of thioacetamide and 4.2 g. of 4-bromoacetylpyridine hydrobromidein 350 ml. of methanol is refluxed for 0.5 hour. The reaction mixture isconcentrated to give a solid residue, to which are added water andsodium hydroxide solution. The aqueous alkaline solution is extractedwith chloroform. The chloroform extracts are dried and concentrated. Theresidue is recrystallized from cyclohexane to give pale yellow crystals,melting point 6972.5 C.

Example 4.Preparation of 4-(2-cyclopropyl-4- thiazolyl pyridine Amixture of 3 g. of cyclopropanethiocarboxamide and 4.2 g. of4-bromoacetylpyridine hydrobromide in 250 ml. of methanol is refluxedfor 1 hour. The reaction mixture is concentrated under reduced pressureto give a yellow solid. Water and sodium hydroxide solution are added tothe solid residue and the resulting alkaline solution is extracted withchloroform. The chloroform extracts are dried and concentrated to givean amber oil. Evaporative distillation at 90-100 C./0.1 mm. gives theproduct as a colorless oil.

Example 5.Preparation of 4-(2-methyl-5-thiazolyl) pyridine A mixture of1.5 g. of 4-acetylaminoacetylpyridine and 2.3 g. of phosphoruspentasulfide is heated in an oil bath at 110-140 C. until gas evolutionceases. The solid mass is heated with excess 1 N potassium hydroxidesolution, and the resulting mixture is extracted with chloroform. Thechloroform solution is dried and concentrated to an amber oil. Thematerial is sublimed at 70 C./0.05 mm. to provide colorless crystals,melting point 30 C.

Example 6.Preparation of 4-(2-oxazolyl)pyridine A solution of 4.3 g. ofN-(2,2-diethoxyethyl)isonicotinamide, 22 ml. of concentrated sulfuricacid, and 0.5 g. of phosphorus pentoxide is heated at C. for 20 minutesand then poured onto 300 ml. of ice. The solution is made basic withsodium hydroxide and extracted with chloroform. The chloroform solutionis dried over anhydrous magnesium sulfate and concentrated to a tansolid. Recrystallization from hexane provides colorless needles, meltingpoint 102-103 C.

Example 7.-Preparation of 4-(5-methyl-2-oxazolyl) pyridine A solution of3.6 g. of a-isonicotinamidoacetone and 4.4 ml. of 85% phosphoric acid in50 ml. of acetic anhydride is refluxed for 1.5 hours. The reactionmixture is cooled and the excess solvent is decanted leaving an oilyresidue. The oily residue is treated with dilute sodium hydroxidesolution to give a white solid. Recrystallization from water givescolorless crystals, melting point 98.5-99.5 C.

Example 8.Preparation of 4-(2-methyl-5-oxazolyl) pyridine Example9.-Preparation of 1-methyl-4-(4-methyl-2- thiazolyl)pyridinium chlorideA mixture of 10.5 g. of 4-(4-methyl-2-thiazolyl)pyridine and 10 ml. ofmethyl chloride is heated at 120 C. in a bomb for 18 houre. The excessmethyl chloride is allowed to evaporate, and the residue isrecrystallized from acetonitrile to allord yellow crystals, meltingpoint 242-244 C., dec.

Example l0.Preparation of 1-methyl-4-(4-methyl-2- thiazolyl)pyridiniumiodide A solution of 3.9 g. of 4-(4-methyl-2-thiazolyl)pyridine, 4 ml.of methyl iodide, and 35 ml. of methanol is heated under reflux for 3hours. The solution is cooled, and the solid which separates iscollected and recrystallized from isopropyl alcohol-water to provideyellow crystals, melting point 218 C., dec.

Example 11.-Preparation of l-ethyl-4-(4-methyl-2- thiazolyl)pyridiniumbromide A mixture of 5.2 g. of 4-(4-methyl-2-thiazolyl)pyridine and ml.of ethyl bromide is heated at 120 C. in a bomb for 18 hours. The excessethyl bromide is removed, and the residue is recrystallized fromacetonitrile to afford pale yellow crystals, melting point 197.5198.5C., dec.

Example 12.Preparation of l-n-propyl-4-(4-methyl- 2-thiazolyl)pyridiniumbromide A solution of 5.2 g. of 4-(4-methyl-2-thiazolyl)pyridine and 5ml. of l-bromopropane in 50 ml. of n-propyl alcohol is refluxed for 18hours. The solvent is removed under reduced pressure and the residue isrecrystallized from acetonitrile to afford pale yellow crystals, meltingpoint 199201 C., dec.

Example 13.Preparation of l-allyl-4-(4-methyl-2- thiazolyl)pyridiniumchloride A mixture of 5 .2 g. of 4-(4-methyl-2-thiazolyl) pyridine and 5ml. of 3-chloropropene is heated at 120 C. in a bomb for 18 hours. Theexcess 3-chlonopropene is removed and the residue is recrystallized fromacetonitrile to afford pale yellow crystals, melting point 189l90 C.,dec.

Example l4.-Preparation of 1-(2-ethoxyethyl)-4-(4-methyl-2-thiazolyl)pyridiuium chloride A mixture of 5.2 g. of4-(4-methyl-2-thiazolyl)pyridine and 5 ml. of 2-chloroethyl ethyl etheris heated at 90 C. in a bomb for 18 hours. The excess 2-chloroethylethyl ether is evaporated and the solid residue is recrystallized fromacetonitrile-ether to afford yellow crystals. Recrystallization fromacetone affords pale yellow needles, melting point 89-92 C.

Example 15.Preparation of 1-methyl-4-(5-methyl- 2-thiazolyl)pyridiniumiodide A solution of 1.2 g. of 4-(5-methyl-2-thiazolyl)pyridine and 5ml. of methyl iodide in 30 ml. of ethanol is heated under reflux for 1hour. The reaction mixture is concentrated to dryness and the crudeproduct is recrystallized from ethanol-ether to give yellow needles,melting point 238239 C., dec.

Example 16.Preparation of 1-methyl-4-(2-methyl- 4-thiazolyl)pyridiniumchloride A mixture of 2.6 g. of 4-(2-methyl-4-thiazolyl)pyridine and 5ml. of methyl chloride is heated at 120 C. in a bomb for 18 hours. Theexcess methyl chloride is allowed to evaporate, and the residue isrecrystallized from ethanol-ether to give tan crystals, melting point228231 C., dec.

Example 17.Preparation of 1-ethyl-4-(2-methyl- 4-thiazolyl)pyridiniumbromide A mixture of 2.6 g. of 4-(2-methyl-4-thiazolyl)pyridine and 5ml. of ethyl bromide is heated at C. in a bomb for 18 hours. The excessethyl bromide is allowed to evaporate, and the residue is recrystallizedfrom acetonitrile to afford tan crystals, melting point 201202 C., dec.

Example 18.Preparation of l-n-propyl-4-(2-methyl- 4-thiazolyl)pyridiniumbromide A mixture of 2.6 g. of 4-(2-methyl-4-thiazolyl)pyridine and 5ml. of 1-bromopropane is heated at 110 C. in a bomb for 18 hours. Thesemi-solid residue is dissolved in acetonitrile. Ether is added to theacetonitrile solution to aflord a sticky solid, which is recrystallizedfrom acetone to give tan crystals, melting point 121123 C.

Example 19.-Preparation of 1-allyl-4-(2-methy1- 4-thiazolyl)pyridiniumchloride A mixture of 2.6 g. of 4-(2-methyl-4-thiazolyl)pyridine and 5ml. of 3-chloropropene is heated at C. in a bomb for 15 hours. Theexcess 3-chloropropene is removed under reduced pressure, and theresidue is recrystallized from acetonitrile to produce pale yellowcrystals, melting point -l67 C., dec.

Example 20.--Preparation of 1-(2-methylallyl)-4-(2-methy1-4-thiazolyl)pyridinium chloride A mixture of 2.6 g. of4-(2-methyl-4-thiazolyl) pyridine and 5 ml. of 3-chloro-2-methylpropeneis heated at 110 C. in a bomb for 18 hours. The solid residue isrecrystallized from acetonitrile to give a tan solid, melting point 186C.

Example 2l.-Preparation of 1-(2-ethoxyethyl)-4-(2-methyl-4-thiazolyl)pyridinium chloride A mixture of 2.6 g. of4-(2-methyl-4-thiazolyl) pyridine and 5 ml. of 2-chloroethyl ethyl etheris heated at 110 C. in a bomb for 18 hours. The dark solid residue iswashed with cold acetone and then recrystallized from acetone to affordpale yellow crystals, melting point 79.5-80" C.

Example 22.--Preparation of 1-methyl-4-(2-cyclopropyl-4-thiazolyl)pyridinium iodide A mixture of 4.5 g. of 4-(2-cyclopropyl-4-thiazolyl)pyridine and 10 ml. of methyl iodide in 50 ml. of ethanol is refluxedfor 1.5 hours. The reaction mixture is concentrated to a smaller volumeand the solid residue is collected. Recrystallization from acetonitrilegives yellow crystals, melting point 233234 C., dec.

7 Example 23.Preparation of 1-methyl-4-(2-methyl- -thiazolyl)pyridiniumiodide A solution of 1.8 g. of 4-(2-methyl-5-thiazolyl) pyridine and 5ml. of methyl iodide in 30 ml. of ethanol is heated under reflux for 1hour. The reaction mixture is concentrated to dryness and the crudeproduct is recrystallized from ethanol-ether to give yellow crystals,melting point 253255 C., dec.

Example 24.-Preparation of 1-methyl-4-(2-oxazolyl) pyridinium chloride Amixture of 2.1 g. of 4-(2-oxazolyl) pyridine and ml. of methyl chlorideis heated at 100 C. in a bomb for 4 hrs. The excess methyl chloride isallowed to escape, and the residual solid is recrystallized fromisopropyl alcohol to provide tan crystals, melting point 244 C., dec.

Example 25.Preparation of 1-methy1-4-(5-methyl- 2-oxazolyl)pyridiniumiodide A solution of 1 g. of 4-(5-methyl-2-oxazolyl)pyridine and 5 ml.of methyl iodide in ml. of ethanol is refluxed 1 hour, cooled andfiltered to remove the product as a yellow crystalline solid.Recrystallization from ethanol-ether gives yellow crystals, meltingpoint 212.5- 214 C., dec.

Example 26.Preparation of 1-methyl-4-(2-methyl- 5-oxazolyl)pyridiniumiodide A solution of 0.7 g. of 4-(2-methyl-5-oxazolyl) pyridine and 3ml. of methyl iodide in 20 ml. of ethanol is heated under reflux for 1hour. The reaction mixture is cooled and the crude solid product iscollected and washed with ether. Recrystallization from ethanol-ethergives yellow crystals, melting point 234-235 C., dec.

Example 27.Preparation of 1-ethyl-4-(2-oxazolyl) pyridinium bromide Amixture of 2 g. of 4-(2-oxazolyl)pyridine and 5 ml. of ethyl bromide isheated at 110 C. in a bomb for 4 hours. The excess ethyl bromide isallowed to evaporate and the residue is recrystallized fromethanol-ether to give off-white crystals, melting point 202203 C., dec.

8 Example 28.-Preparation of 1-allyl-4-(2-oxazolyl) pyridinium chlorideA mixture of 2 g. of 4-(2-oxazolyl)pyridine and 5 ml. of 3-chloropropeneis heated at C. in a bomb for 4 hours. The excess 3-chloropropene isdistilled, and the residue is recrystallized from ethanol-ether to givetan crystals, melting point 202-203 C., dec.

We claim:

1. The method of lowering blood glucose levels in warm-blooded animalswhich comprises orally administering to said animals a blood glucoselowering amount of a pyridinium salt of the formula:

wherein R is selected from the group consisting of hydrogen, methyl andcyclopropyl; R is selected from the group consisting of alkenyl, of 3 to4 carbons, alkyl, of 1 to 4 carbons, and ethoxyethyl; X is selected fromthe group consisting of sulfur and oxygen and Y is a pharmaceuticallyacceptable anion.

2. The method of claim 1, in which the pyridinium salt is: 1 methyl 4(2-cyclopropyl-4-thiazolyl)pyridinium iodide.

3. The method of claim 1, in which the pyridinium salt is: 1-allyl-4-(2-oxazolyl pyridinium chloride.

4. The method of claim 1, in which the pyridinium salt is:1-(2-ethoxyethyl)-4-(4-methyl-2-thiazolyl)pyridinium chloride.

5. The method of claim 1, in which the pyridinium salt is:l-methyl-4-(2-methy1-4-thiazolyl)pyridinium chloride.

References Cited FOREIGN PATENTS 875,887 8/1961 Great Britain 424-2631,020,805 2/1966 Great Britain 424263 STANLEY J. FRIEDMAN, PrimaryExaminer F. E. WADDELL, Assistant Examiner

